Textile crimping

ABSTRACT

An improved crimper for wool and other fibres employs a feed section and a conveyor or delivering section in which the fibre layer advances at a slower speed than in the feed section, the two sections being separated by a folding zone sufficiently small to ensure that the layer is folded therein into simple folds or waves of amplitude dependent upon the spacing of the conveyor surfaces. The improved feed section is constituted by a roller and a curved plate, the latter being spaced from the roller at its intake end and conforming closely to the roller nearer the folding zone. The roller and/or the plate may be resiliently biased towards the operating position, for example by being mounted on a resiliently biased, pivoted arm. Provision may be made for applying steam to the fibres in the folding zone.

United States Patent Hutchinson et al.

[451 Jan. 22, 1974 TEXTILE CRIMPING [75] Inventors: Peter Hutchinson, llkley; Geoffrey Darnbrough, Wetherby, both of England [73] Assignee: T.W.S. Nominee, Company Limited,

London, England [22] Filed: Mar. 9, 1972 [21] Appl. No.: 233,221

[30] Foreign Application Priority Data Mar. 16, 1971 Great Britain 7,007/71 [52] US. Cl. 28/l.6, 28/7214 [51] Int. Cl D02g 1/112 [58] Field of Search 28/16, 72.14

[56] References Cited UNITED STATES PATENTS 2,908,044 10/1959 Whitney 28/l.6

2,938,258 5/1960 Starkie 3,253,314 5/1966 Shattuck 28/l.6

Primary Examiner-Louis K. Rimrodt Attorney, Agent, or Firm-Harold L. Stowell et al.

[ ABSTRACT An improved crimper for W001 and other fibres employs a feed section and a conveyor or delivering section in which the fibre layer advances at a slower speed than in the feed section, the two sections being separated by a folding zone sufficiently small to ensure that the layer is foldedtherein into simple folds or waves of amplitude dependent upon the spacing of the conveyor surfaces. The improved feed section is constituted by a roller and a curved plate, the latter being spaced from the roller at its intake end and conforming closely to the roller nearer the folding zone. The roller and/or the plate may be resiliently biased towards the operating position, for example by being mounted on a resiliently biased, pivoted arm. Provision may be made for applying steam to the fibres in the folding zone.

13 Claims, 4 Drawing Figures ATENT'LU SM? SMET 3 OF 4 TEXTILE CRIMPING The present invention relates to the mechanical folding of textile fibres into corrugated form, and more especially, but not exclusively, to the folding of fibres of relatively low tensile strength such as wool.

There is described in our copending German application No. 1,948,756 an apparatus for crimping textile fibres which comprises at least one feed belt cooperating with a substantially parallel opposed surface for holding and advancing an unfolded strand or layer of textile fibres, at least one conveyor belt cooperating with and spaced a predetermined distance from an opposed surface for holding and conveying a folded strand or layer, and optionally at least one steam conduit having a steam outlet orifice at the intake end of the conveyor belt, and means for driving the feed belt at a higher surface speed than the conveyor belt, the output end of the feed belt being so closely adjacent to the intake end of the conveyor belt that a fibre strand or layer passing from the one belt to the other will become folded into substantially simple folds or waves having an amplitude determined by the predetermined spacing between the conveyor belt and the cooperating surface opposed thereto.

In the feed mechanism for the above apparatus there is normally used one or more textile belts coupled to a drive mechanism. It is an object of the invention to provide a crimper having a further improved and simplified feed mechanism.

Accordingly the present invention provides a method of producing folded textile fibres which comprises forwarding and flattening a layer of textile fibres between a feed roller rotating at a first speed and a curved guide plate closely spaced from and conforming to the roller surface, and discharging the flattened layer from the opening defined by the roller and the discharge end of the guide plate into a folding zone between the said opening and a pair of spaced substantially parallel conveyor belts driven at a second speed slower than the first, whereby the layer of fibres becomes folded normal to its plane into simple folds or waves having an amplitude and pitch dependent on the spacing between the conveyor belts and the relationship between the second speed and the first speed.

In another aspect, the present invention provides a device for crimping textile fibres, especially wool fibres, comprising a feed roller and a curvilinear guide plate having an intake portion spaced apart from the roller, and a forwarding portion conforming to and closely spaced from the roller surface for forwarding a flattened layer of fibres, the discharge end of the plate defining with the surface of the roller an opening for the advancing layer of textile fibres, a pair of cooperating spaced substantially parallel conveyor belts driven at the same speed, and means for driving the feed roller at a higher surface speed than the conveyor belts, the said opening being adjacent to the intake end of the conveyor belts and positioned so that the layer of fibres passing from the opening to the conveyor belts is folded normal to its plane into substantially simple folds or waves having an amplitude dependent upon the predetermined spacing between the conveyor belts. The feed plate is conveniently S-shaped as shown in the attached drawings.

In the apparatus of the invention, it is preferred to use a pair of flexible conveyor belts which are of wire mesh. In one embdoiment the opening defined by the feed roller and the curvilinear guide plate directs the advancing silver of wool downwardly into the folding zone and onto the lower conveyor belt where it becomes spontaneously folded normal to its plane into simple folds or waves. The guide plate is preferably rotatably mounted trunnions on the axis of the feed roller and provided with an adjustable stop for adjusting the position of the opening defined by the guide plate and the surface of the roller relative to the intake of the conveyor belts. It is preferred that the guide plate is biased towards its forward position, conveniently by a spring.

In another embodiment the feed roller or both the feed roller and cooperating guide plate are resiliently mounted so as to be movable away from the conveyor belts in the event of a blockage and consequent buildup of fibres in the crimping zone. This resilient mounting reduces the risk of damage to the conveyor belts. Preferably the feed roller and plate are mounted on an arm pivotally mounted on the frame of the machine and means are provided for resiliently clamping the arm in the operating position.

The term fibres as used herein includes both staple fibres and continuous filaments, and slivers, slubbings, tops, rovings and yarns.

It has been found that improved results are obtained with the present type of crimper if the fibres being folded are subjected to a treatment to bring them into a plasticised condition in the folding zone, conveniently by subjecting them to a steam treatment as they are folded and conveyed through the folding zone. Accordingly the crimping device is preferably provided with a steam conduit at the intake end of the conveyor belt transversely disposed to the direction of the movement of the fibres, and having an orifice for jetting steam onto the fibres.

It may also be preferred to apply setting agents onto the fibres in the folding zone, examples being reducing agents and bases (e.g., MEAS (monoethanolamine sulphite) and MBA).

Although the invention may be applied to various forms of fibrous layer, it is particularly advantageous for the fibres to be supplied in the form of a flat sliver. When a sliver of fibres is treated by the method just defined, it is folded normal to its plane into a corrugated wave form and, since the back pressure on the sliver from the folded portions further ahead can be kept to a minimum, little fibre damage need be incurred. Though folding normal to the plane of the sliver is a preferred feature of the invention, folding of the fibres in the plane of the sliver can also take place and is included within the invention. Depending upon whether in-plane folding occurs in addition to the out-of-plane folding, the individual fibres will exhibit crimp in a single plane (sinusoidal crimp) or will be crimped in three dimensions (helical crimp).

The product of the present invention has novel characteristics which distinguish it from the products of prior crimping processes and devices, and more especially from fibres crimped in stuffer box crimpers. Fibres folded in accordance with the invention exhibit a regular wave form with rounded wave crests. Fibres crimped in stuffer boxes, on the other hand, are irregularly crimped and have sharp angles separated by straight leg lengths, and it is at the sharp angles where damage occurs.

For a given spacing between the guide plate and the feed roller, there is a maximum permissible distance between the opening defined therebetween and the intake of the spaced conveyor surfaces (i.e., a maximum size of the folding zone), beyond which the layer will deviate from its general direction of movement to such an extent that complex and irregular folding occurs, and the form of the product will then begin to resemble that characteristic of stuffer box crimpers.

The positions of the feed rollers and the S-shaped guide plate can readily be adjusted to provide the re quired dimensions and shape in the crimping zone so that the fibre layer is folded normal to its plane into simple folds in the manner described above.

It has moreover been observed that in the apparatus for folding fibres in accordance with the invention, the distance apart of the opening for the advancing layer of textile fibres and the intake between the spaced conveying surfaces for holding the folded strand, which distance effectively defines the dimensions of the folding zone, are of the same order of magnitude as each other and of the amplitude of the folds produced.

For a given amplitude, the pitch of the folds or waves, that is to say the distances from one peak to the next in the folded material, is principally determined by the ratio between the speeds of advance of the unfolded layer and conveyance of the folded material.

The fibres may be set in their crimped condition while confined between the pair of conveyor belts. In the case of synthetic fibres, the fibres may be folded in the heated condition, and may merely require to be cooled. Fluid setting agents can be applied through the feed or conveyor belts, where these are permeable. Where wool is to be crimped, steam is often employed for the purpose of setting the crimp with or without treatment of the wool with a setting reagent, and for this purpose the conveyor belts may be permeable and pass through a steam chamber. Provision may also be made for applying steam to the sliver before it is crimped, in order to condition it for the folding operation. Setting agents may be applied to the wool at any stage before steaming is complete, either by spraying on the fibres while they are confined between permeable belts, by padding the sliver in a solution of the reagent before it enters the crimping device, or by any other convenient means.

With the method and device according to the invention, as contrasted with stuffer box crimpers, control of the dimensions of the imparted crimp is relatively easy. The level of crimp can be conveniently defined in terms of two factors, namely, the crimp frequency which is the number of crimp waves per unit length of crimped sliver, and crimp height. In a stuffer box crimper the level of crimp is determined by the back pressure of the crimped fibre mass in the crimping chamber, and these factors are not easily controlled independently.

In considering crimp height and crimp frequency, it must be understood that the crimp height and frequency of individual fibres taken from a set, crimped sliver in accordance with the invention is not necessarily the same as the crimp height and frequency of the crimped sliver as such. Moreover, the crimp height and frequency of a set, crimped sliver must be distinguished from the amplitude and pitch of the folds initially imparted to the sliver, as discussed above. The relationship between the dimensions of the initial folds and that of the final set crimp, depends on the efficiency of the setting operations on the fibres concerned.

Nevertheless, it remains true that in crimping fibres in accordance with the invention, the height of the crimp can be controlled directly by the spacing of the conveyor surfaces. Thus in the preferred apparatus, the crimp height of the sliver is increased by increasing the distance between the conveyor belts, and is decreased by decreasing this distance. As the crimp height increases, the crimp frequently decreases. However, at a given belt spacing, crimp frequency can be controlled by the relative speeds with which the sliver is advanced and conveyed on opposite sides of the folding zone, namely by the ratio of the speed of the feed roller to the conveyor belt speed, which may be termed the feed ratio. As this ratio is increased, with a given spacing of the conveyor belts, more crimps of the same height are formed per unit length of crimped sliver. The level of crimp in the sliver may easily be altered while the machine is in motion by altering the feed ratio or the belt gap so as to provide variably crimped sliver.

This control is particularly easy to effect with feed ratios within the range of 2:1 to 6:1. Where the feed ratio is less than 2:1, and the conveyor belts are already in contact, or have a very small gap of, for example, 0.005 inch, a flat crimp wave is formed. As the feed ratio is increased the back pressure on the sliver is increased, and at feed ratios of 6:1 or above sensitive fibres such as wool may suffer undesirable damage. With wool fibres, the preferred feed ratios are between 3:1 and 4:1. The feed ratio in a given case may be higher than the ratio of the unfolded to folded sliver length. This is due to slippage between the sliver and the feed roller which depends on the frictional characteristics of the roller and the sliver and the tension of the stationary feed plate against the sliver. As the feed ratio is increased, at a constant feed roller speed, so the crimp frequency increases and the crimp angle decreases and the un-crimping" forces in the sliver increase. Where steam is employed to set wool fibres, the efficiency of setting depends on the time of steaming and steaming time adequate at low feed ratios may be found inadequate at high feed ratios.

It has surprisingly been found that the roller feed mechanism of the invention gives a greater contraction of the crimped yarn than that obtainable using a textile belt in the feed mechanism. Furthermore, at feed ratios of about 5:1, and below, the roller feed also gives a higher crimp frequency than the belt feed. Such a result is especially desirable because the ability to produce a high degree of crimp at low feed ratios means that the back pressure on the wool and risk of damage to the wool fibre can be yet further reduced.

Other factors affecting the crimp produced arise from the nature and dimensions of the fibrous strand being folded. Other things being equal, a thick sliver gives a higher crimp height and frequency than a thin sliver. Flexible fibres are more readily crimped than less flexible, and thus with the same setting of the device and in slivers of equal weight, Merino fibres exhibit greater crimp frequency than New Zealand Crossbred wool, which are of greater diameter.

in folding slivers of wool fibres, spacings of the spaced conveyor belts found most satisfactory are from 1 to 5 mm. However, in crimping yarns in the same apparatus, as described below, the preferred spacing is 1 3 mm; at higher spacings the yarns tend to spread sideways and the desired effects are not achieved.

A further important aspect of the present invention is the treatment of yarns in the apparatus defined and described above. Yarns so treated have very different properties from yarns made from crimped fibres.

The effect produced on yarn by a device according to the invention depends largely on the space available to the yarn as it leaves the feed roller, that is, in the folding zone. The available space is determined by the spacing of the conveyor surfaces, the feed ratio and the density of the yarn feed. If an individual yarn is fed, it can move freely sideways in the folding zone, but if many yarns are fed in together side by side, as must be done according to the present invention, to form the equivalent of a dense sliver, the sideways movement of the yarn is restricted and the yarn will take up a different crimped form.

The invention will be further described by means of one example of a folding and crimping apparatus, reference being made to the accompanying drawings, in which FIG. 1 shows a diagrammatic cross sectional view of an apparatus for crimping fibres according to the invention',

FIG. 2 is a detailed diagram showing the folding zone of the apparatus of FIG. 1',

FIG. 3 is an end view showing one example of a feed mechanism of this invention; and

FIG. 4 is a side view of a preferred feed mechanism for the crimper.

The apparatus shown in the drawings comprises a feed roller and a co-operating S-shaped guide plate 11 having an intake portion spaced apart from the surface of the roller surface and a remaining portion conforming generallyto the curvature thereof. The discharge endof the guide plate 11 defines with the surface of the roller 10 an opening in the form of a slit. The spindle 12 of the feed roller is supported by bearings in a mounted bracket 13 fixed to the machine frame 14 and has a drive wheel 15 connected by a chain drive 16 passing over rollers 17 and 18 to a motor 19 having a clutch (not shown).

The opening formed between the roller 10 and guide plate 11 is positioned closely adjacent to the entrance between a pair of permeable wire mesh conveyor belts 20 and 21. The lower portion of the upper belt 20 is closely spaced from and parallel to the upper portion of the lower belt 21 and cooperates with it to hold and convey folded textile fibres. The conveyor belts pass over guide rollers 22 and 23 and wedge-shaped guide blocks 24 and 25 having curved bearing surfaces for the belts, which surfaces have a radius of curvature of about 2mm and are provided with steam jet pipes 26 and 27 having a plurality of jet orifices for directing steam into a folding z0ne between the conveyor belts 20 and 21 and the surface of the roller 10. The belts pass through a steaming chamber 28 and a drying chamber 29. They pass additionally over guide rollers 30 and 31 and tensioning rollers 32 and 33 are driven at a speed lower than the surface speed of the feed roller by drive rollers 34 and 35 connected to a motor 36. (The drive for the upper belts 20 is not shown).

The guide plate 11 is secured to a reinforcing bar 37 for preventing distortion of the plate, which in turn is mounted on trunnions 38 on the spindle 9 and is resiliently fixed to the trunnions. The ends 39 of the reinforcing bar 37 are urged towards adjustable nuts 40 on the trunnions by compression springs 40 cooperating with pressure adjusting nuts 42. The guide plate is additionally provided with a projection 43 carrying an ad- 5 justable stop screw 44 whose position can be fixed by a locknut 45. A tension spring 46 is provided between the projection 43 and a suitable surface on the block 24 over which the belt 20 passes. The guide plate 11 is urged clockwise by the action of the spring 46 until the stop-screw 44 makes contact with the block 24. The position of the plate 11 and therefore of the opening formed between the plate and the roller 10 relative to the intake to the feed belts 20 and 21 can be adjusted as required by operation of the stop-screw44.

In operation, a sliver of wool fibres is fed between the guide plate 11 and the roller 10 which is rotated clockwise (as seen in FIGS. 1 and 2) by the motor 19. As the sliver is forwarded by the action of the roller 10 it is compressed between the guide plate 11 and the roller and is discharged as a flattened sliver at the slitlike opening between the discharge end of the guide plate and the roller. The sliver passes into a folding zone between the said opening and the entrance to the pair of belts 20 and 21, which are driven at a speed lower than the surface speed of the roller 10. The sliver of fibres becomes folded substantially normal to its plane, and during the folding operation the individual fibres become plasticised by a current of steam di rected from the steam pipes 26 and 27 onto the fibres as they pass through the folding zone. The folded fibres are confined between the closely spaced parallel portions of the belts 20 and 21, and pass through the steaming zone 28 wherein a current of steam is directed onto the fibres for setting the crimp and then through the drying zone 29 where the fibres are dried by warm air. The crimped and set fibres are then conveyed to the point at which the belts 20 and 21 diverge and there discharged.

In FIG. 4 which illustrates a preferred mounting for the feed roller and plate, there are shown conveyor belts 20 and 21 which pass over guide rollers 22 and 23, and guide blocks 24 and 25 with steam jet pipes 26 and 27, as previously described. A roller 402 is mountd on an arm 403 supported by a pivot 404 on a mounting bracket 405 which is bolted to the machine frame. A clamping nut 406 between the arm 403 and a slot in the side of the bracket 405 limits the movement of the arm 403. An S-shaped guide plate 401 is supported from a bracket fixed to the frame of the machine. The plate 401 can be brought into proximity with the roller 402 and is provided with a radial adjustment screw 407 for adjusting its position relative to the intake between the belts 20 and 21 and a pressure adjustment screw 408 for adjusting the downward pressure exerted by a spring 409 on the plate 401. The position of the roller 402 relative to the belts is adjusted by an adjustment screw 410 which is mounted on the bracket 405 and cooperates with a stop 411 on the arm 403 to limit the closeness with which roller 402 approaches the belts. The arm 403 is urged towards the belts by a spring 412 cooperating with a sleeve 413 which is urged against a toggle clamp 414, shown in the closed position. Two sliver guides 415 are provided to direct a wool sliver feed towards the intake formed between the roller and plate.

When the toggle clamp 414 is open the roller 402 can move away from the belts 20 and 21. The plate 401 can also be withdrawn by raising it from its position against the roller. When the clamp 414 is in the closed position, a predetermined compression is put on the spring 412 and is sufficient to hold the roller adjacent to the belts in the operating position determined by the adjustment screw 410. Sliver can be fed in between the roller and plate and crimped as described. In the event of a blockage in the crimping zone leading to a build-up of fibres, pressure against the roller 402 causes the spring 412 to be compressed and the arm 403 carrying the roller and plate moves away from the belts 20 and 21. Excessive pressures and damage in the crimping zone can therefore be avoided. The clamp 414 is then opened to enable the obstruction to be cleared, after which it can be closed and the machine restored to normal operation.

It will be apparent that many variations can be made in the constructions described. For example the arrangement of FIG. 4 can be modified by mounting the spring-biased plate 401 on an extension of the arm 403 instead of on a separate bracket of the frame. This has the advantage that the plate 401 does not require readjustment when the roller 402 is moved away from the belts and subsequently returned to the operating posi' tion, and it may well prove to be the preferred arrangement. The crimping of wool according to the invention will now be described by reference to the following Example:

EXAMPLE Belt Feed Feed Frequency Contraction Ratio (crimps/cm) 3:1 1.40 55.0 4: l 2.00 6 l 77 5:1 2.40 68.0 6: l 3.01 69.0 7: l 3.62 69.9

What is claimed is: l. A method of producing folded textile fibres which comprises the steps of:

forwarding and flattening a layer of textile fibres between a feed roller rotating at a first speed and a curved guide plate closely spaced from and conforming to the roller surface; discharging said flattened layer from an opening defined by the roller and the discharge end of the guide plate into a folding zone between the said opening and a pair of spaced substantially parallel moving conveyor surfaces said layer being unsupported in said zone and said zone having dimensions of the same order as said spacing; causing said layer of fibres in said zone to become folded normal to its plane into simple folds or waves; and withdrawing said folded layer from said folding zone between said conveyor belts moving at a second speed slower than said first speed, said folds or waves having an amplitude and pitch dependent on the spacing between said conveyor belts and the relationship between said second speed and said first speed.

2. A method according to claim 1, including the step of subjecting said fibres to a steam treatment as they are folded and pass through said folding zone.

3. A method according to claim 1, including the ste of applying a setting agent to said fibres.

4. A method according to claim 1, including the steps of:

conveying said folded layer to a setting zone; and setting the folds or waves in said setting zone to provide set crimped fibres.

5. A method according to claim 4, wherein said fold or wave setting step is conducted while the strand or layer is confined between said spaced conveyor surfaces.

6. A method according to claim 1 wherein the layer comprises keratinous fibres such as wool.

7. A device for crimping textile fibres comprising:

a feed roller;

a curvilinear guide plate having an intake portion spaced apart from the roller and a forwarding portion conforming to and closely spaced from the roller surface, defined by the surface of the roller and the discharge end of said plate defining an opening for an advancing layer of textile fibres;

a pair of co-operating spaced substantially parallel conveyor belts having an intake end;

means for driving said conveyor belts; and means for driving said feed roller at a higher surface speed than said conveyor belts;

said opening being closely adjacent to the intake end of the conveyor belts to form a folding zone of dimensions of the same order as the spacing of said belts, said zone being free of support for the fibres therein such that a layer of fibres passing from said opening to the conveyor belts is foled normal to its plane into substantially simple folds or waves having an amplitude dependent upon the predetermined spacing between said conveyor belts.

8. A device according to claim 7 in which said feed plate is S-shaped.

9. A device according to claim 7 in which at least one of said roller and feed plate is resiliently biased towards the operating position.

10. A device according to claim 9 including an arm whereon said at least one of said roller and feed plate is mounted; said arm being resiliently biased towards said operating position.

11. A Device according to claim 7 wherein the conveyor belts comprise wire mesh.

12. A device according to claim 7 including setting means for setting the fibres in the folded or waved condition.

13. A device according to claim 7 including a steam conduit at the intake end of the conveyor belts, said conduit being transversely disposed to the direction of movement of the fibres and defining at least one orifice for directing steam onto the fibres. k i t 1 f 2339 UNITEii STATES PATENT OFFICE CERTIFICATE OF CORRECTION Paten N 3.786.538 Dated January 22. 1974 lnventofls) PETER 1101mm 3 ON and GEOFFREY DARNBROUGH It-is certified that era-or appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

f" Item 73; Column 1 of the above-identified patent,

change "T.W.S." to read -I.W.S.-.

si d and sealed this. 3rd day of September 1974.

(SEAL) Attest:

McCOY GIBSQN, JR. C. MARSHALL DANN Attestlng offlccr Commissioner of Patents 

1. A method of producing folded textile fibres which comprises the steps of: forwarding and flattening a layer of textile fibres between a feed roller rotating at a first speed and a curved guide plate closely spaced from and conforming to the roller surface; discharging said flattened layer from an opening defined by the roller and the discharge end of the guide plate into a folding zone between the said opening and a pair of spaced substantially parallel moving conveyor surfaces said layer being unsupported in said zone and said zone having dimensions of the same order as said spacing; causing said layer of fibres in said zone to become folded normal to its plane into simple folds or waves; and withdrawing said folded layer from said folding zone between said conveyor belts moving at a second speed slower than said first speed, said folds or waves having an amplitude and pitch dependent on the spacing between said conveyor belts and the relationship between said second speed and said first speed.
 2. A method according to claim 1, including the step of subjecting said fibres to a steam treatment as they are folded and pass through said folding zone.
 3. A method according to claim 1, including the step of applying a setting agent to said fibres.
 4. A method according to claim 1, including the steps of: conveying said folded layer to a setting zone; and setting the folds or waves in said setting zone to provide set crimped fibres.
 5. A method according to claim 4, wherein said fold or wave setting step is conducted while the strand or layer is confined between said spaced conveyor surfaces.
 6. A method according to claim 1 wherein the layer comprises keratinous fibres such as wool.
 7. A device for crimping textile fibres comprising: a feed roller; a curvilinear guide plate having an intake portion spaced apart from the roller and a forwarding portion conforming to and closely spaced from the roller surface, defined by the surface of the roller and the discharge end of said plate defining an opening for an advancing layer of textile fibres; a pair of co-operating spaced substantially parallel conveyor belts having an intake end; means for driving said conveyor belts; and means for driving said feed roller at a higher surface speed than said conveyor belts; said opening being closely adjacent to the intake end of the conveyor belts to form a folding zone of dimensions of the same order as the spacing of said belts, said zone being free of support for the fibres therein such that a layer of fibres passing from said opening to the conveyor belts is foled normal to its plane into substantially simple folds or waves having an amplitude dependent upon the predetermined spacing between said conveyor belts.
 8. A device according to claim 7 in which said feed plate is S-shaped.
 9. A device according to claim 7 in which at least one of said roller and feed plate is resiliently biased towards the operating position.
 10. A device according to claim 9 including an arm whereon said at least one of said roller and feed plate is mounted; said arm being resiliently biased towards said operating position.
 11. A Device according to claim 7 wherein the conveyor belts comprise wire mesh.
 12. A device according to claim 7 including setting means for setting the fibres in the folded or waved condition.
 13. A device according to claim 7 including a steam conduit at the intake end of the conveyor belts, said conduit being transversely disposed to the direction of movement of the fibres and defining at least one orifice for directing steam onto the fibres. 